Tub drain and bath tub liner

How does the drain hardware in a tub liner interface with the drain in the original tub? Can the liner drain be removed (disconnected) from the tub drain without damaging the liner?

You may not have a choice on that if you need to snake a drain.
It should be fine though.

Terry...........I guess I don't understand your reply. I am trying to find out if it is possible to remove the drain assembly in a tub liner which now has water between the liner and the tub. It appears that the water has entered under the flange of the liner drain. If I could remove the liner drain that would (theoretically) give the trapped water access to the original tub drain. I don't know if the liner drain is just a "press fit" into the tub drain or held in place by some other means. There must be someone out there who is familiar with how these things are put together. Thanks for any help you can provide.

Well.............as a plumber, I've always seen those installed with standard tub waste and overflows.
And yes, we sometimes notice that water gets between the old tub and the new liner.

They don't make "special" drains for that purpose.

Here is a post by hj on that.

The water goes in around the perimeter or the overflow opening. The drain is TIGHT, otherwise the water would have drained out. You have to remove the drain "strainer" so the water can drain, and then put it back in. That has been a problem with just about every tub liner I have ever seen. hj​

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Usually, the drain is just sandwiching the old tub and the new liner together to make the seal. Water could get between them either from there if the sandwich isn't tight enough, or maybe from the overflow if the liner and tub aren't sandwiched tight there. So, loosening the drain basket should allow it to drain. The stagnet water might be pretty raunchy. As to how to prevent it from happening, that's tougher. Not sure how flexible the liner is, whether they glued it to the tub there with maybe some silicon, and didn't get it perfect, or were just relying on the compression from the drain to sandwich it together and seal.

Terry......Thanks for your thoughts. The reply from hj was the first one I got. The drain/stopper mechanism is a step-on type with a knob on the top that you grab and pull up to open the drain. The knob can be unscrewed which reveals the top of a shaft on which the stopper rides up and down. The shaft screws into a cross piece about 1-1/4" lower down in the drain. This cross piece looks like it is attached to the bottom of the liner drain. Below the cross piece I can see the original tub drain which runs to the left and, out of sight, intersects with the pipe coming down from the overflow opening. We never use the tub as a soaking tub. It is strictly used as a shower. That said, the overflow hardware is tight and no water is getting in that way. I think water must be getting in via the drain opening. The chrome flange around the stopper mechanism must not be tightly sealed. If I could somehow grab that liner drain hardware and pull it out, it seems that the water could then drain out. I'm guessing that there must be a tight seal between the liner drain and the tub drain opening (per hj's suggestion) which prevents the water from draining between showers. The question remains, is the liner drain hardware held in place just by caulk and friction? If so, I should be able to work it loose and pull it out without damaging the liner. What I don't know is if there may be a nut threaded onto the liner drain on the bottom side of the liner. If that is the case, obviously I won't be able to pull it out. I hope there is someone out there who has put one of these together (or ripped one out) who can answer that last question. Thanks for any help.

You don't snake a tub through the drain shoe at the bottom. You go through the overflow plate.

Common cause of slow drain is hairs right at the drain flange area, and a ZipIt strip works wonders on that.